Conventionally, there is a device that automatically switches an irradiation direction of a headlight up/down depending on whether or not an oncoming vehicle, a preceding vehicle, or the like is present. The device detects a light source, such as the headlight of an oncoming vehicle or the like, from an image of a region ahead of a vehicle captured by a camera, considers the oncoming vehicle or the like to be present when the light source is detected, and switches the irradiation direction of the headlight of the vehicle (see PATENT DOCUMENT 1).